Pump



April 4, 1967 H. B. scHuLTz 3,312,169

- PUMP Filed Jan. 18, 1965 2 Sheets-Sheet 1 INVENTOR.

kw/4M April 4 1967 H. B. scHuL'rz 3,312,169

PUMP

.950 /4/6 ya 2524 0a 75a. 76

I N VENTOR.

HAROLD 5. SCh'l/LTZ H T TOE/VE Y of Delaware Filed 1an. 18, 1965, Ser..No. 426,116 6 Claims. (Cl. 103-37) This invention relates to lahydraulic pump, and more particularly to a hydraulic pump whichincorporates a pressure regulator and is provided with ported inductionfeatures.

` Several problems of varying degrees of severity have arisen in theearly phases of development of high pressure, small displacement,hydraulic pumps. These included high speed piston float, failure tolimit positively the maximum pump pressure, and poor pump primingcharacteristics caused by large clearance volume in the pumping chamberin combination with fluid aeration. It is, therefore, a principal objectof my invention to provide an inexpensive, economical and practical pumpsolving all the aforesaid problems.

It is a further specific object of my invention to provide a pump with:a regulating valve which maintains a predetermined maximum outputpressure.

It is yet another object of my invention to provide a pump having asmaller clearance volume for a pump inlet valve .arrangement byutilizing the principle of ported induction.

Yet, still another 'particular object of my invention lies in theprovision of a pressure balanced cylinder assembly which moves out asIaccumulator pressure acting on a small piston exerts a force greatenough to overcome that of a regulating spring on the cylinder assemblywhereby the inlet for the pump is always open whereby the displacementvolume of the pump may be regulated in accordance with the needs of asystem therewith associated.

Other objects and advantages of my invention will appear from thefollowing description of the drawings in which:

FIGURE l is a schematic presentation of a power braking system utilizinga pump in accordance with the principles of my invention;

FIGURE 2 is a cross-sectional view of a pump embodying features inaccordance with the principles of my invention; and

FIGURE 3 is ya cross-sectional view of a modified form of pump embodyingprinciples of my invention.

Referring particularly to FIGURE l, `a power brake system as showncomprising a power brake control valve 19 having split fluid dischargeports 12 and 14 and a single inlet port 16 receiving fluid from aconduit 1S that is connected with :a fluid discharge side of anaccumulator 20 which is connected to a pump 22 designed in accordancewith the principles of my invention. As seen, the pump 22 iscommunicated to the accumulator by means of a conduit 24 and to a fluidreservoir 26 by means of a conduit 28. The fluid reservoir 26 is alsocommunicated with the control valve in order to replenish fluid supplytherewithin when the control valve is in the released attitude shown.

The control valve is operated by means of a brake pedal 30 connectedthereto by means of push rod 32.

The fluid discharve ports 12 and 14 are communicated to wheel cylinders34 and 36, respectively, of a front brake means 3S and a rear brakemeans 40, respectively.

The pump 22 is driven by means of a fan belt 42 from a vehicle engine(not shown) that rotates a pulley 44 keyed or otherwise axed to apumpshaft46.

The fluid discharge conduit 24 is connected to the pump at a fluiddischarge port 48; whereas the reservoir ired States Patent O ICCconduit 23 is connected to the pump 22 at a reservoir port 59. The pumpmay be mounted to the aforesaid engine by means of the mounting flanges52 and 54 formed on the pump housing.

Referring now to FIGURE 2, I show across section of my pump 22 showingit to be constructed generally from a tubular housing 56 having aradially open end 58 and an axially open end 60 which is threaded as at62 to receive a plug 64. The radial opening is closed by means of afiller cap 66 held in place by ia split ring 68 which filler cap isformed with a means to receive conduit 28y to supply reservoir fluid tothe cavity within housing 56. The housing is also provided with journalbearings (not shown) which receive the shaft 46 of the pulley 44. Asseen in FIGURE 2, the shaft 46 is provided with an eccentric throw 79 onwhich 1a pitman 72 is journaled so that rotary motion for shaft 46 willtransmit reciprocatory motion to pitman 72.

The pitman 72 is formed with a spherical surface 74 to receive aspherical rod end 76 for a piston 78.

The piston 78 is reciprocatorily arranged within a cylinder assemblythat includes a cylinder block 80, a cylinder head 82 which is joined tothe cylinder block as by the threads 34, a sleeve 86 formed withradially displaced axial openings 88 and a central opening 99 which issized to slip over an annular base projection of the cylinder block S9and abut upon a radial flange of the cylinder block, as seen. Theaforesaid cylinder Aassembly is biased by means of -a spring 92 bearingupon a spring retainer bearing plate 94 which is operatively connectedto the cylinder block to the right as viewed in FIGURE 2 to project fromthe plug 64.

The cylinder head 82 is formed with a discharge cavity 96 ahead of theinnermost end of the cylinder block, which cavity is communicated bymeans of a tube 98 to a passage 100 in an annular fitting 102 positionedwithin an axial bore 104 within the plug 64, as by a bearing 106 andsnap ring 108. The fitting 162 is provided with a peripheral seal 119and an inner seal 112. The inner seal 112, as well as the bearing 106i,cooperates with the tube 98 to prevent fluid discharge pressure Ifromleaking out of the passage 100 and to support the tube 9S in the plug64.

In the constructions shown by FIGURES 2 and 3 l have equated the outerdiameter of tube 98 to the outer diameter of piston 78. By virtue of thefact that these diameters are equal, any pressure in the pumping ordischarge cavity 96 and passage 190 does not disturb a balancedcondition created by biasing spring 92 against a piston 126.

It has been my experience that if one does not equate the diameters ofthe aforesaid members, then the designer is forced to utilize a largespring and a large piston to minimize :the unbalance effects caused bypumping. Therefore, I have been able to produce a compact and efficientpump Without utilizing spring loads which aggravate assembly problems.

The passage 100 is closed by means of a check valve 114 heldthereagainst by a spring 116 that is compressed between the check valve114 and a plastic fitting 118 abutting `the -axial end of the bore 164in the plug 64. The fitting 118 is provided with radial passages 120 sothat upon opening of the check valve 114 as by discharge pressure inpassage 11MB greater than the compressive force of spring 116, fluidwill flow outwardly into an annular chamber 122 which is open to anaxial passage 124 through the plug 64 leading to the discharge port 48.

Centrally of the fitting 118 l have provided a pressure responsivemember or piston 126 that is subjected to the pressure passing throughcheck valve 114 at one end thereof and bears upon a cross pin 128 at theother end thereof.

The cross pin 128 is connected to the sleeve 86 by a tight fit therewithand to the plug 64 through an elongated slot 130. The cylinder block Stiis provided with a radial fluid inlet passage 132 which is located tocommunicate when assembled to the cylinder head 82 with a radial opening134 in the cylinder head that is open to an inlet chamber 136 betweenthe sleeve S6 and the cylinder block and cylinder head. As seen, thechamber 136 is communicated by means of axial openings 88 to a reservoirchamber 138 to be lled with a hydraulic fluid or the like.

In FIGURE 3 I -have shown a slight variation of the aforesaid pumpassembly wherein a housing 55a is provided with internal passages 13S,140 and 142 so that fluid within the discharge chamber 12251 may becommunicated to the pressure responsive member 12661 that is locatedremotely from the plug 64a and operative against a bearing plate 144 forpushing the sleeve 86a that is in abutment with cylinder block Stiaagainst the compressive force of the spring 92a to function similarly tothat of the pump of FIGURE 2 which will be explained below. Thesubscript a indicates similar elements as presented in FIGURE 2.

Two other features that distinguish the construction of FIGURE 3 fromthat of FIGURE 2 are the use of an additional spring retainer 146 toabut on the right face of the plug 64a and in the use of a spring clip14S for retaining the spherical end 7dr: of the piston '78a to thepitman 72a, which connection in FIGURE 2 was by means of a simple snapt.

More simply stated, in the embodiment of FIGURE 2 We pull the sleeve 36;whereas in the embodiment of FIGURE 3 we push the sleeve 36a.

In operation, the shaft 46 is rotated by pulley 44 through drive belt 42to reciprocate the eccentric 70 and thereby reciprocate piston 78 withinthe cylinder block and cylinder head. As seen, the piston 78 never fullyopens the radial port 132 in the cylinder block and in the restposition, or rearward position, as shown, allows fluid to enter throughthe cylinder head into the cylinder block ahead of the piston. Uponmoving inwardly of the cylinder block, the piston closes off the inletand pressurizes the uid brought therein until sufcient pressure isreached to open a discharge valve 150 against its spring 152 whereuponfluid will pass through the tube 98 into the passage 100. Until thepressure in t-he accumulator builds up to a predetermined amount, thefluid within the passage 10G will open the check valve 114 to ow throughlthe plug 64 to the accumulaton However, when a predetermined pressurein the accumulator has been reached, the pressure responsive member 126will be caused to move to the left to push |the pin 128 and pull thecylinder 86 to the left also. This has the effect of reducing thedisplacement Volume 0f the piston 78 as the cylinder block is caused tomove to a position where the inlet 132 and companion inlet 134 in thecylinder head 82 is held open for an increasing portion of the pumpingcycle. When accumulator pressure reaches system pressure, the inductionport (132 and 134 combined) is held open for the full pumping cycle andpump displacement is reduced to zero.

I claim:

1. A pump comprising:

a housing having an internal bore which is threaded at one end thereof;

a reciprocating piston operatively connecte-d in said housing at the endopposite that which is threaded;

a cylinder assembly operatively connected to said housing by saidthreads thereon including,

a threaded plug member having a discharge passage and a discharge portcommunicated therewith which is communicated with an annular dischargechamber, said plug also having an elongated slot therein,

a sleeve operatively connected to said plug by a cross pin that extendsthrough said elongated slot of said plus,

a cylinder block and head assembly operatively connected to said plug bya spring that causes abutting relationship of said block with saidsleeve, said cylinder block and head assembly having an internal borereceiving said reciprocating piston, said internal Ibore of saidcylinder block and head assembly being open radially to a chamber formedwithin said sleeve about said cylinder block and head assembly whichradial opening is located to be open by said piston when said piston isat the bottom of its reciprocatory motion to allow fluid to enter saidbore ahead of said piston,

a discharge valve means operatively associated with said bore in saidcylinder block and head assembly which is operable upon the creation ofa predetermined pressure within said bore to discharge iiuid from saidcylinder block and head assembly, and

a tubular means of equal diameter as said piston, said tubular meansoperatively connecting said cylinder block and head assembly t-o saidannular chamber in said plug.

2. A pump according -to claim 1 and fur-ther comprising a pressureresponsive member operatively connected to said pin and to said annularchamber in said plug so as to compress said spring holding said cylinderblock and head assembly to said plug whenever the pressure acting uponsaid pressure responsive means is greater than the compressiveresistance of said spring to thereby move said radial port of saidcylinder block and head assembly forwardly of said piston whereupon saidport will be held open for an increasing portion of the pumping cycle toreduce the displacement of said pump until the displacement of said pumpis reduced to zero when said radial port is open for the full pumpingcycle.

3. A pump comprising:

a housing having a reservoir supply port and an axially located internalbore with a radially displaced passage open at one end to said axialbore and at the other end to a closed chamber within said housing;

a plug aixed to an open end of said bore affixed to said housing closingan open end of said bore, said plug having an axial passage and a radialpassage leading from said axial passage to said passage communicatedwith the radial displaced passage in said hous- 111g;

a cylinder block and head assembly having an axial discharge tube and aradial inlet port, which cylinder block and head assembly is biased by aspring away from said plug;

a sleeve for limiting the projection of said cylinder block and headassembly from said plug;

a piston of equal external diameter as said tube, said piston beingreciprocatorily arranged within said housing for pressurizing a luid insaid cylinder block and head assembly, said piston having a maximumretractile position which would open said radial port to allow fluid toenter said cylinder block and head assembly;

a pressure responsive means responsive to the discharge pressure of saidcylinder block and head assembly for positioning said cylinder blockand-head assembly within said housing, which pressure responsive meansis located in said closed chamber of said housing and operativelyconnected to said sleeve in opposition to said spring.

4. A pump comprising: a housing having an internal bore with an outletpassage;

a cylinder block and head assembly within said housing, said assemblyhaving an inlet port, a pressure responsive discharge valve and anoutlet tube of a predetermined outside diameter operatively connected tothe head on the opposite side thereof as the cylinder block with thedischarge valve interposed;

a piston operatively connected to the housing and mounted forreciprocation within the cylinder block and head assembly for developinga uid pressure 6. A pump according to claim 4 wherein the operativetherein, said piston having a diameter equal to the connection betweensaid pressure responsive mem'ber and predetermined outside diameter ofsaid outlet tube; said sleeve utilizes said spring to position saidsleeve as a spring between said housing and said cylinder block well assaid assembly within said bore.

and head assembly to position said assembly in said 5 bore; ReferencesCited by the Examiner a means operatively connected to said outletpassage UNITED STATES PATENTS `and said assembly in opposition to saidspring to regulate the position of said inlet port, which means 1g;'llzazram includes a check valve to prevent outlet pressure fromreturning to said cylinder block and head as- 10 3160102 12/1964 Budzlch10?*37 3,205,832 9/1965 Daub 103-37 sembly during retractile motion ofsaid piston. 5. A pump according to claim 4 wherein said means LAURENCEV EFNER Pfl-mary Examiner consists of a pressure responsive member and asleeve operatively connected to said member.

1. A PUMP COMPRISING: A HOUSING HAVING AN INTERNAL BORE WHICH ISTHREADED AT ONE END THEREOF; A RECIPROCATING PISTON OPERATIVELYCONNECTED IN SAID HOUSING AT THE END OPPOSITE THAT WHICH IS THREADED; ACYLINDER ASSEMBLY OPERATIVELY CONNECTED TO SAID HOUSING BY SAID THREADSTHEREON INCLUDING, A THREADED PLUG MEMBER HAVING A DISCHARGE PASSAGE ANDA DISCHARGE PORT COMMUNICATED THEREWITH WHICH IS COMMUNICATED WITH ANANNULAR DISCHARGE CHAMBER, SAID PLUG ALSO HAVING AN ELONGATED SLOTTHEREIN, A SLEEVE OPERATIVELY CONNECTED TO SAID PLUG BY A CROSS PIN THATEXTENDS THROUGH SAID ELONGATED SLOT OF SAID PLUG, A CYLINDER BLOCK ANDHEAD ASSEMBLY OPERATIVELY CONNECTED TO SAID PLUG BY A SPRING THAT CAUSESABUTTING RELATIONSHIP OF SAID BLOCK WITH SAID SLEEVE, SAID CYLINDERBLOCK AND HEAD ASSEMBLY HAVING AN INTERNAL BORE RECEIVING SAIDRECIPROCATING PISTON, SAID INTERNAL BORE OF SAID CYLINDER BLOCK AND HEADASSEMBLY BEING OPEN RADIALLY TO A CHAMBER FORMED WITHIN SAID SLEEVEABOUT SAID CYLINDER BLOCK AND HEAD ASSEMBLY WHICH RADIAL OPENING ISLOCATED TO BE OPEN BY SAID PISTON WHEN SAID PISTON IS AT THE BOTTOM OFITS RECIPROCATORY MOTION TO ALLOW FLUID TO ENTER SAID BORE AHEAD OF SAIDPISTON, A DISCHARGE VALVE MEANS OPERATIVELY ASSOCIATED WITH SAID BORE INSAID CYLINDER BLOCK AND HEAD ASSEMBLY WHICH IS OPERABLE UPON THECREATION OF A PREDETERMINED PRESSURE WITHIN SAID BORE TO DISCHARGE FLUIDFROM SAID CYLINDER BLOCK AND HEAD ASSEMBLY, AND A TUBULAR MEANS OF EQUALDIAMETER AS SAID PISTON, SAID TUBULAR MEANS OPERATIVELY CONNECTING SAIDCYLINDER BLOCK AND HEAD ASSEMBLY TO SAID ANNULAR CHAMBER IN SAID PLUG.